The present invention relates to a hinge assembly for household appliances having an horizontally-pivoted front door.
More specifically, the present invention relates to a hinge assembly for a home dishwasher having an horizontally-pivoted front door, and to a front-loading dishwasher provided with such hinge assembly, implementation to which the following description refers purely by way of example without implying any loss of generality.
As is known, today's front-loading dishwashers generally comprise a substantially parallelepiped-shaped, outer casing which is structured for resting on the floor, and is provided with an inner washing chamber which communicates with the outside through a substantially rectangular crockery loading/unloading opening formed in the vertically-oriented front wall of the casing; a substantially rectangular-shaped front door which is pivotally-jointed to the front wall of the casing via two lateral hinge assemblies structured to allow free rotation of the door about a horizontally-oriented rotation axis which is located immediately beneath the access opening to the washing chamber; and usually two dish-racks which are housed inside the washing chamber one above the over, and are fixed to the inner surface of the washing chamber in drawer-like manner so to be manually extractable from the washing chamber through the crockery loading/unloading opening on front wall of the casing.
More specifically, the two hinge assemblies are located on opposite sides of the front door, close to the lower horizontal edge of the door, and are aligned one another so as to allow manual rotation of the door about the door rotation axis, between a raised position in which the front door is oriented substantially vertically and rests completely against the front wall of the casing to close the crockery loading/unloading opening and watertight seal the washing chamber, and a lowered position in which the front door is oriented substantially horizontally, beneath the crockery loading/unloading opening, so as to give the user free access to the washing chamber via the crockery loading/unloading opening.
Each hinge assembly of currently marketed front-loading dishwashers usually comprises: a first coupling plate which is substantially perpendicular to the front-door rotation axis and is structured for being firmly fixed to a corresponding vertical lateral wall of the casing, immediately adjacent the crockery loading/unloading opening of the front wall; a second coupling plate which is structured for being firmly fixed to the door side body, and is pivotally jointed to the first coupling plate so as to be able to rotate about the door rotation axis, between a first working position wherein the front door of the dishwasher is arranged in the raised position, and a second working position wherein the front door of the dishwasher is arranged in the completely lowered position; and finally a door-weight balancing device which is interposed between the first and the second coupling plate and it is structured for elastically hampering rotation of the second coupling plate with respect to the first coupling plate from the first to the second working position, so as to get a very slow lowering of the front door.
Additionally, several models of hinge assembly currently on the market are also structured so as to allow an on-site adjustment of the hampering effect of the door-weight balancing device, according to the actual weight of the front door. This solution avoids an on-site replacement of the standard hinge assemblies when a particularly heavy covering panel is firmly fixed to the front door of the dishwasher to hide the household appliance. This problem is typical of built-in front-loading dishwashers and similar household appliances.
Hinge assemblies having an on-site adjustable door-weight balancing device are disclosed in DE3140039 and EP1602883.
The main drawback of the hinge assembly disclosed in DE3140039 is that the on-site adjustable door-weight balancing device is too complicated to tune up because the user is requested to act on two distinct adjusting mechanisms, namely the front screw and the internal sleeve, and only one of these adjusting mechanisms is directly accessible from the front wall of the casing.
The main drawback of the hinge assembly disclosed in EP1602883 is that the on-site adjustable door-weight balancing device is structured to allow only a few step-by-step discrete adjustments of the hampering effect of the door-weight balancing device. Moreover the elastic member of the on-site adjustable door-weight balancing device is a tensile-stressed helical spring which traditionally has a non linear response to loads, with all problems concerned.